Filopodia on neuronal growth cones: multi-functional structures with sensory and motor capabilities

Abstract Pathfinding decisions, as neuronal growth cones navigate their complex embryonic terrain, are largely determined by the fan-shaped array of filopodia at the leading edge of the advancing growth cone. These sensory/motor extensions of growth cones locally receive, process, and react to information from their environment. Recent advances in our knowledge of the mechanisms by which extracellular signals cause changes in the concentration of the second messenger calcium and by which calcium affects growth cone function have provided substantial insights into the chain of events occurring in filopodia that help guide growth cones to their appropriate targets.